The present invention relates to a low temperature sinterable and low loss dielectric ceramic compositions for use in fabricating various high frequency devices such as a multilayer chip capacitor, a multilayer chip filter, a multilayer chip capacitor inductor composite device and module, a low temperature sinterable substrate, a resonator or a filter and a ceramic antenna, and its method.
Recently with the rapid development in a mobile communication and a satellite communication, a high frequency dielectric ceramics is in a high demand as a material for a high frequency integrated circuit or a dielectric resonator.
Major characteristics of the dielectric ceramics used for a high frequency includes a high dielectric constant (xcex5r), a quality factor (Q) and a stable and tunable temperature coefficient (xcfx84f) of a resonance frequency.
Representative high frequency dielectric compositions which have been widely known up to now are (Zr, Sn)TiO4 group, BaOxe2x80x94TiO2 group, (Mg, Ca)TiO3 group, and Baxe2x80x94(Zn1/3Ta2/3)O3, Ba(Mg1/3Ta2/3)O3, Ba(Zn1/3Nb2/3)O3 as Ba-peropskite group etc.
However, these compositions are disadvantages in that they are mostly fired at a high temperature of 1,300xcx9c1,500xc2x0 C., phase synthesis is not easy, a dielectric constant is low or a high-priced material should be used.
Besides, lately, advancement of a portable information communication devices lead to development of various types of substrates and multi-chip module (MCM) by a multilayer chip high frequency devices or low temperature co-firing ceramics (LTCC), and a research and development of a low temperature firing high performance high frequency ceramics are conducted accordingly.
However, there are problems that the performance of the high frequency characteristic is considerably degraded such as, for example, most of them are not sufficient in terms of density when being fired at a low temperature, a dielectric constant is decreased according to addition of a sintering aid, a quality factor is degraded and a temperature factor is changed.
In addition, silver or copper conduct with a small high frequency loss and a cofiring available low temperature firing high frequency dielectric ceramic are very rare.
Therefore, an object of the present invention is to provide a dielectric ceramics composition which can be fired at a very low temperature but has an excellent high frequency dielectric characteristic of various temperature compensation characteristics according to a high quality factor, a dielectric constant, a stable temperature factor and a composition, and can be implemented at a low cost.
Another object of the present invention is to provide a dielectric ceramics composition which can employ Ag, Cu, their alloy or a Ag/Pd alloy as an internal electrode and thus be used for various high frequency devices, such as a multilayer chip capacitor, a multilayer chip filter, a multilayer chip capacitor/inductor composite device and a low temperature sinterable substrate, a resonator and a filter or a ceramic antenna.
In order to achieve the above objects, there is provided a dielectric ceramics composition which is constructed by combining 1 mole of (Zn1xe2x88x92xMx) TiO3 and yTiO2(0xe2x89xa6yxe2x89xa60.6 as a main component, one of 0xcx9c5 wt % B2O3, 0xcx9c5 wt % H3BO3, 0xcx9c5 wt % SiO2xe2x80x94K2O glass, 0xcx9c5 wt % B2O3 and SiO2xe2x80x94K2O glass, or 0xcx9c5 wt % H3BO3 and SiO2xe2x80x94K2O glass is added as an additive thereto, and fired at a low temperature of 800xcx9c925xc2x0 C., its preparation method, and a high frequency dielectric ceramics device using the same. In this respect, xe2x80x98Mxe2x80x99 is one of Mg, Co, Ni, xe2x80x98xxe2x80x99 is 0xe2x89xa6xxe2x89xa60.55 in case of Mg and xe2x80x98xxe2x80x99 is 0xe2x89xa6xxe2x89xa61 in case of Co, and 0xe2x89xa6xxe2x89xa61 in case of Ni